Tobacco smoke filter and method of production

ABSTRACT

A product rod comprising a plurality of individual tobacco smoke filters or filter elements abutted end to end; and a wrapper engaged around the plurality of filters or filter elements, the wrapper including perforations.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of prior U.S. application Ser. No. 14/403,364,filed Nov. 24, 2014, which was the National Stage of InternationalApplication No. PCT/EP2013/060732, filed May 24, 2013, which claimspriority to Great Britain Application No. 1209345.6, all of which arehereby incorporated by reference in their entireties.

The present invention relates to tobacco smoke filters or filterelements and methods of their production.

Non-Wrapped Acetate (NWA) filters are well-known in the art. Typically,NWA filters comprise a self-sustaining body of continuous crimpedcellulose acetate filaments bonded at their points of contact. NWAfilters are characterized from conventional cigarette filters becausethe former do not require a separate plugwrap to wrap the filter andhold the fibrous bundle in place with a controlled circumference. NWAfilters may be manufactured by a process similar to that described in UKPatent No. 1169932 (U.S. Pat. No. 3,455,766).

NWA filters may be sold as Pop-a-Tip™ filters for Roll-Your-Own (RYO)Smokers; they are well known and available from Filtrona Filters.Pop-a-Tip filters comprise a series of NWA filters (filter tips) wrappedin a transparent film e.g. made of BOPP or cellophane—e.g. six 14 mmfilters contained in a Pop-a-Tip rod of 84 mm length. The NWA filtersare individually pushed (or ‘popped’) out of the transparent wrap bysmokers of RYO products, who then use the filter when rolling theircigarette. NWA filters are preferred over more conventional wrappedacetate (WA) filters, because it is much more difficult to ‘pop’ a WAfilter from the transparent film due to increased frictional forces.However, the product can be tricky to use as a certain amount ofdexterity is required to push the filter tips out from the surroundingfilm (e.g. some bending and flexing of the Pop-a-Tip may be necessary).In addition, the empty film-wrap needs to be separately discarded,creating a potential additional littering problem.

It is, of course, possible, for RYO smokers to buy loose individual tipsand these are typically supplied in plastic bags. Such bags of tips areinconvenient for smokers to carry around; a further advantage ofPop-a-Tips is that they are of similar dimensions to a cigarette and canbe packaged and sold in a packs that are much easier for the consumer tocarry (e.g. similar to a cigarette pack).

Accordingly, it would be desirable to have a product that resembles a‘Pop-a-Tip’ and can be packaged in a similar way; from which individualfilters are more readily and easily extractable by the consumer; andwhich does not have the attendant expense and littering associated withthe transparent overwrap. The present invention achieves theseobjectives.

According to the present invention in a first aspect there is provided aproduct rod comprising a plurality (e.g. two or more, e.g. 4-6) ofindividual tobacco smoke filters or filter elements abutted end to end;and a (common) wrapper engaged around the plurality of filters or filterelements, the wrapper including perforations. The individual tobaccosmoke filters (or individual tobacco smoke filter elements) arepreferably (substantially) identical (with each other). In other words,the product rod preferably comprises a plurality (e.g. two or more, e.g.4-6) of individual identical tobacco smoke filters or individualidentical filter elements abutted end to end; and a (common) wrapperengaged around the plurality of filters or filter elements, the wrapperincluding perforations.

According to the invention in a further aspect there is provided aproduct rod comprising a plurality (e.g. two or more, e.g. 4-6) ofindividual tobacco smoke filters or filter elements abutted end to end;and a (common) wrapper engaged around the plurality of filters or filterelements, the wrapper including a line of perforations (holes) inregister with the or each junction between abutted filters or filterelements (that is, in register with each region where adjacent filtersor filter elements abut each other). The individual tobacco smokefilters (or individual tobacco smoke filter elements) are preferably(substantially) identical (with each other). In other words, the productrod preferably comprises a plurality (e.g. two or more, e.g. 4-6) ofindividual identical tobacco smoke filters or individual identicalfilter elements abutted end to end; and a (common) wrapper engagedaround the plurality of filters or filter elements, the wrapperincluding a line of perforations (holes) in register with the or eachjunction between abutted filters or filter elements.

Herein, the term identical means the same (equal, alike); in other wordseach individual filter has such a close similarity or resemblance to theothers as to be essentially equal or interchangeable.

It will be appreciated that each (individual) filter may include morethan one filter element. Thus, each (individual) filter may be a dual ortriple filter, as is well known in the art.

The wrapper may be a paper (e.g. a plugwrap) or other sheet material.The paper is preferably a paper having basis weight of 15-50 gsm, morepreferably 17-35 gsm.

The paper may be air permeable, or impermeable (i.e. air impermeableexcept where the holes have been generated). The wrapper may be acellulosic film or a cellulosic based film. The wrapper may bebiodegradable. Preferably the wrapper has the ‘Ready Biodegradability’level of biodegradability as measured according to OECD 301B ‘ReadyBiodegradability’ method (modified Sturm test), which is well known inthe art.

The product rod of the invention allows the smoker to easily pull orbend the product rod at each join (junction between abutted filters) tosnap off individual filters/elements. The perforations (holes) at eachjunction between abutted filters/elements allow a clean break betweenabutting filters/elements to be achieved; a jagged break would beunsightly and unacceptable to the consumer. The (outer) wrapper of thesnapped-off filter forms part of the filter tip to be used, rather thanbecoming redundant (as in the case of conventional Pop-a-Tips). Both WA(wrapped acetate) and NWA filters can be used in this product,increasing flexibility for the filter manufacturer.

Preferably the wrapper includes a line of 16 to 40, e.g. 16 to 39, e.g.20 to 35, e.g. 30 to 35 perforations (holes) in register with the oreach junction between abutted filters or filter elements. Preferably thewrapper includes a line of 20 to 35 perforations (holes) in registerwith the or each junction between abutted filters or filter elements,for a product rod of approximate circumference 17.5 mm. The wrapper mayinclude a line of 20 to 40 perforations (holes) in register with the oreach junction between abutted filters or filter elements, for a productrod of approximate circumference 17.5 mm. The perforations (holes) maybe any shape, e.g. oval or rectangular. Preferably the perforations(holes) are symmetrical. Oval shaped perforations (holes) are morepreferred because they provide a cleaner break in the paper. Rectangularor similar perforations (holes) may be aligned so that their longer sideis orientated either across the width or along the length of thewrapper.

The perforations (holes) may be made by any means known in the art, e.g.laser, mechanical means or electrostatic means. Preferably, theperforations (holes) are visible to the naked eye (e.g sufficientlylarge that the consumer can see them on the outside of the product rod,enabling him to clearly identify the point at which the rod should besnapped). The (e.g. laser perforated) perforations (hole) dimensions maybe 0.1 mm to 0.7 mm along one or both edges. The (e.g. laser perforated)perforations (holes) are preferably spaced at 10 to 25 holes per cm(along the line of perforations), more preferably 11 to 23 holes per cm(along the line of perforations). Preferably the perforations (holes)are of nominal dimensions 0.6 mm×0.3 mm, e.g. 0.4×0.2 mm. The applicantshave found that perforations (holes) of this size give a good visualcue.

Research (see Example) has shown that 30 to 35 rectangular or ovalshaped holes of nominal dimensions 0.4×0.2 mm around the circumferenceof a 17.9 mm circumference product rod provide optimum ‘snap’characteristics. Less than around 15 holes of such size give an uneven‘snap’ (e.g. with unacceptable tearing), whilst more than 40 holes canresult in the paper wrapper being too weak to be processed onconventional filter making and/or packaging machinery. It will beappreciated that a proportionately greater or lesser number of holeswould be required for filter products of higher or lower circumference.

According to the present invention in a still further aspect there isprovided a product rod comprising a plurality of (e.g. two or more, e.g.4 to 6) individual tobacco smoke filters or filter elements abutted endto end; and a (common) wrapper engaged around the plurality of filtersor filter elements, the wrapper including a line of perforationsextending from one end of the product rod to the other end and defininga helix about the periphery (outer surface) of the product rod. In thisaspect the consumer peels back a strip along the helical line ofperforations to allow filters/filter elements to be sequentiallyreleased for use, the remaining wrapper holding the remaining filters inplace. The individual tobacco smoke filters (or individual tobacco smokefilter elements) are preferably (substantially) identical (with eachother). In other words, the product rod preferably comprises a plurality(e.g. two or more, e.g. 4-6) of individual identical tobacco smokefilters or individual identical filter elements abutted end to end; anda (common) wrapper engaged around the plurality of filters or filterelements, the wrapper including a line of perforations extending fromone end of the product rod to the other end and defining a helix aboutthe periphery (outer surface) of the product rod.

In a preferred example, the pitch of the helix defined by the line ofthe perforations (that is the distance along the helical axis thatresults in one full turn of the helix) is the length of a singleindividual filter or filter element. In this example, peeling back thestrip along the line of perforations for a single turn of the helixreleases a single filter/filter element.

The perforations (holes) may be any shape, e.g. oval or rectangular.Preferably the perforations (holes) are symmetrical. Oval shapedperforations (holes) are more preferred because they provide a cleanertear in the paper. The perforations (holes) may be made by any meansknown in the art, e.g. laser, mechanical means or electrostatic means.The (e.g. laser perforated) perforations (hole) dimensions may be 0.1 mmto 0.7 mm along one or both edges. The (e.g. laser perforated)perforations (holes) are preferably spaced at 5 to 25 holes per cm(along the line of perforations), for example 10 to 25 holes per cm(along the line of perforations), for example 11 to 23 holes per cm(along the line of perforations). It will be appreciated that for ahelical line of perforations the requirement for a clean break, ratherthan tearing, is less important and the holes may be spaced furtherapart. Preferably the perforations (holes) are of nominal dimensions 0.6mm×0.3 mm, e.g. 0.4×0.2 mm. Preferably the holes (e.g. oval holes) areoriented with their longest axis (i.e. the hole length) perpendicular tothe line of perforations.

The wrapper may be a paper (e.g. a plugwrap) or other sheet material.The paper is preferably a paper having basis weight of 15-50 gsm, morepreferably 17-35 gsm. The paper may be air permeable, or impermeable(i.e. air impermeable except where the holes have been generated). Thewrapper may be a cellulosic film or a cellulosic based film. The wrappermay be biodegradable. Preferably the wrapper has the ‘ReadyBiodegradability’ level of biodegradability as measured according toOECD 301B ‘Ready Biodegradability’ method (modified Sturm test), whichis well known in the art.

The individual (e.g. identical or substantially identical) filters orfilter elements may include a substantially cylindrical core of tobaccosmoke filtering material. The individual filter or filter element mayfurther comprise a further wrapper. The further wrapper may be a paper(e.g. plugwrap).

The (individual) (e.g. identical or substantially identical) filters orfilter elements may comprise a self-sustaining (longitudinallyextending) cylindrical core. Herein, the term “self-sustaining” (as in“self-sustaining substantially cylindrical core”, “self-sustaininglongitudinally extending substantially cylindrical core” etc.) meansstable, rigid and self-supporting without requirement for a furtherwrapper (of e.g. plugwrap) to maintain its shape (e.g withoutrequirement for a wrapper to hold the longitudinally extendingcontinuous filaments in alignment to control the radius or circumferenceof the core).

The (individual) (e.g. identical or substantially identical) filters orfilter elements may comprise a self-sustaining (longitudinallyextending) cylindrical core comprising (e.g. formed from) a plurality oflongitudinally extending substantially continuous filaments of tobaccosmoke filtering material (e.g. cellulose acetate tow) which are bondedat their points of contact. In another example, the filters or filterelements may comprise a self-sustaining (longitudinally extending)cylindrical core comprising (e.g. formed from) a plurality of randomlyoriented (e.g. individual or staple) fibres of tobacco smoke filteringmaterial (e.g. cellulose acetate) which are bonded at their points ofcontact.

Preferably the continuous filaments of tobacco smoke filtering material(or randomly oriented fibres of tobacco smoke filtering material) arecontinuous filaments (or randomly oriented fibres) of cellulose acetatetow. Preferably the tobacco smoke filtering material (e.g. celluloseacetate, cellulose acetate fibres or filaments) is crimped. Preferablythe filaments (or fibres) are bonded at their points of contact with abonding constituent, e.g. a plasticiser (e.g. a plasticiser which hasbeen activated or cured to bond the filaments at their points ofcontact). The self-sustaining longitudinally extending cylindrical coremay be, for example, a cylindrical rod of circular cross section. Theself-sustaining longitudinally extending cylindrical core may be ofother shape, for example the self-sustaining longitudinally extendingcylindrical core may be of annular cross section such that theself-sustaining longitudinally extending cylindrical core is alongitudinally extending hollow tube comprising (e.g. formed from)fibres or filaments of tobacco smoke filtering material bonded at theirpoints of contact.

The individual (e.g. identical or substantially identical) filtersand/or filter elements may further comprise one or more continuouscomponents extending substantially longitudinally (e.g. longitudinally)of the cylindrical core. The (or a, or each) continuous component may bea thread or yarn or tape or continuous extruded element, for example acotton thread, a cellulose acetate yarn, or a continuous extrudedelement of e.g. cellulose acetate such as that disclosed inWO2011/058319. Cigarette filters which include a thread or tape element,typically longitudinally aligned therein, are well known in the priorart. They are often referred to as “Thread Filters”. Thread Filters wereoriginally proposed in U.S. Pat. No. 4,281,671, in which a cotton sewingthread was the preferred element. U.S. Pat. No. 4,281,671 also disclosedhow the thread could be coloured, e.g. with different colours denotingdifferent flavours. U.S. Pat. No. 4,281,671 discloses Thread Filterswhich require a wrapper around the tobacco smoke filtering material (andthread); it does not disclose filters or filter elements which include athread but which are self sustaining (i.e. stable, rigid andself-supporting without requirement for a further wrapper).

The (or a, or each) continuous component extending longitudinally of thecylindrical core may be coloured or tinted, e.g. using appropriate dyesor pigments, preferably those with regulatory approval for use in foodcontact applications. The (or a, or each) continuous component may be ofa contrasting colour to the tobacco smoke filtering material. In anexample, the (or a, or each) continuous component further comprises adye or pigment (e.g. a dye or pigment which has regulatory approval foruse in food contact applications). The dye or pigment may preferably beany colour which contrasts with the (e.g. white) tobacco smoke filteringmaterial, for example green, blue, red, orange etc. If two or morecontinuous components extending substantially longitudinally (e.g.longitudinally) of the cylindrical core are present, the firstcontinuous component may be of the same colour, or a different colour,to the second continuous component. The use of coloured component(s)(e.g. coloured cotton thread or threads) provides a product filter,element or rod with a distinctive end appearance that is useful foranti-counterfeit purposes.

The continuous component may bear a smoke modifying agent such as aflavouring agent. The flavouring agent may be any flavouring agent knownfor use in tobacco smoke filters or filter elements. For example, theflavouring agent may be menthol, spearmint, peppermint, nutmeg,cinnamon, clove, lemon, chocolate, peach, strawberry, vanilla etc. Theagent may contain nicotine or a salt or derivative thereof. Preferablythe flavouring agent is menthol.

The individual (e.g. identical or substantially identical) filters orfilter elements may include an additive (e.g. an adsorbent). Theadditive may be a particulate additive. The particulate additive may anyparticulate additive suitable for use in a tobacco smoke filter—e.g.activated carbon, zeolite, ion exchange resin (e.g. a weakly basic anionexchange resin), sepiolite, silica gel, alumina, molecular sieves,carbonaceous polymer resins and diatomaceous earths. The particulateadditive may be a mixture of two, or more, materials. The additive mayinclude a flavourant—e.g. menthol—e.g. the additive may be sepiolitegranules to which menthol has been applied. The individual (e.g.identical or substantially identical) filters or filters element maycomprise a longitudinally extending core of tobacco smoke filteringmaterial and an additive (e.g. carbon) with at least one end free ofadditive (to present a clean end to the smoker). The individual filtersor filters element may be ‘monocarbon’ filters or filter elements—i.e. afilters/elements including a single longitudinally extending core offiltering material and additive (e.g. carbon) that has at least one endfree of additive and e.g. which can be manufactured in a one-passprocess (e.g. the ‘Active Patch’ filter, as disclosed in, for example,GB 2261152, and the ‘Smooth Core’ filter, as disclosed in, for example,WO 2006/059134).

The individual (e.g. identical or substantially identical) filters maycomprise: a downstream (e.g. longitudinally extending, e.g.substantially cylindrical) core of tobacco smoke filtering material; anupstream (e.g. longitudinally extending, e.g. substantially cylindrical)core of tobacco smoke filtering material spaced longitudinally(upstream) of the downstream core; a wrapper (e.g. an outer wrapper)engaged around and joining the spaced upstream and downstream cores todefine a cavity between the spaced upstream and downstream cores. Thefilter may include an additive in the cavity such that the individualfilters are triple granular filters. The tobacco smoke filter or filterelement may be of circumference 14 to 28 mm, for example 16 to 26 mm,for example 16 to 19 mm (e.g. 17.5 mm) or 24 to 25 mm. A tobacco smokefilter of the invention may be of length 10 to 40 mm, e.g. 11 to 25 mm,e.g. 12 to 16 mm, e.g. 14 mm. A tobacco smoke filter element of theinvention may be of length 5 to 30 mm, e.g. 6 to 20 mm, e.g. 8 to 15 mm,e.g. 10 to 12 mm.

Filters and filter elements from product rods according to all aspectsof the invention may be used generally as (or in) a filter tip for usewith a individually rolled cigarette (e.g. a hand rolled cigarette) or aRoll Your Own or Make-Your-Own product.

According to the present invention in a further aspect there is provideda method of producing a product rod comprising a plurality (e.g 2 ormore, e.g. 4 to 6) of individual (e.g. identical or substantiallyidentical) tobacco smoke filters or filter elements abutted end to end,and a wrapper engaged around the plurality of filters or filterelements, wherein the wrapper includes perforations; the methodcomprising:

applying a wrapper to a longitudinally advancing flow comprisingpluralities (groups) of individual (e.g. identical or substantiallyidentical) filters or filter elements arranged between (e.g. pre-formed)dual filter rods, each dual filter rod comprising two (e.g. identical orsubstantially identical) filters/elements joined end to end, wherein thefilters/filter elements and filter rods are abutted end to end [tothereby form a continuous wrapped rod comprising pluralities (groups) ofabutted filters or filter elements arranged between (and abutted to)dual filter rods];

cutting the continuous wrapped rod in register with the dual filter rodssuch that the dual filter rod is cut into two individual filters/filterelements, to thereby provide a plurality of product rods each comprising(e.g. identical or substantially identical) filters or filter elements;

perforating the wrapper (e.g with a laser).

The wrapper may be perforated such that it has a line of perforations inregister with the or each junction between abutted filters/filterelements/dual filter rods. The wrapper may be perforated such that ithas a line of perforations extending from one end of the product rod tothe other end and defining a helix about the periphery (outer surface)of the product rod. The perforations (holes) may be any shape, e.g. ovalor rectangular. Preferably the perforations (holes) are symmetrical. Theperforations (holes) may be made by any means known in the art, e.g.laser, mechanical means or electrostatic means. The (e.g. laserperforated) perforations (hole) dimensions may be 0.1 mm to 0.7 mm alongone or both edges. The wrapper may be perforated with (e.g. laserperforated) perforations (holes) which are preferably spaced at 5 to 25holes per cm (along the line of perforations), for example 10 to 25holes per cm (along the line of perforations), for example 11 to 23holes per cm (along the line of perforations).

Preferably the wrapper is perforated with perforations (holes) ofnominal dimensions 0.6 mm×0.3 mm, e.g. 0.4×0.2 mm. Preferably thewrapper is perforated with the perforations (e.g. oval holes) orientedwith their longest axis (i.e. the hole length) perpendicular to the lineof perforations.

According to the present invention in a still further aspect there isprovided a method of producing a product rod comprising a plurality (e.g2 or more, e.g. 4 to 6) of individual (e.g. identical or substantiallyidentical) tobacco smoke filters or filter elements abutted end to end,and a wrapper engaged around the plurality of filters or filterelements, wherein the wrapper includes perforations; the methodcomprising:

applying a perforated wrapper to a longitudinally advancing flowcomprising pluralities (groups) of individual (e.g. identical orsubstantially identical) filters or filter elements arranged between(e.g. pre-formed) dual filter rods, each dual filter rod comprising two(e.g. identical or substantially identical) filters/elements joined endto end, wherein the filters/filter elements and filter rods are abuttedend to end [to thereby form a continuous wrapped rod comprisingpluralities (groups) of abutted filters or filter elements arrangedbetween (and abutted to) dual filter rods];

cutting the continuous wrapped rod in register with the dual filter rodssuch that the dual filter rod is cut into individual (e.g. identical orsubstantially identical) filters/filter elements, to thereby provide aplurality of product rods each comprising filters or filter elements.

The wrapper may be perforated such that it has a line of perforations inregister with the or each junction between abutted filters/filterelements/dual filter rods. The wrapper may be pre-perforated with(lateral) lines of perforations aligned across the width of the wrapper,each row being separated from the adjacent row by a distancecorresponding to the length of a single filter/filter element. In thecase, the method may include a step of aligning/registering the laterallines of perforations with the junctions between abutted filters/filterelements (e.g. prior to or during wrapping). In another example themethod includes a step of generating—e.g. with a laser—(lateral) linesof perforations across the width of the (non-perforated) wrapper priorto, preferably immediately prior to, application of the wrapper.

The perforations (holes) may be any shape, e.g. oval or rectangular.Preferably the perforations (holes) are symmetrical. The perforations(holes) may be made by any means known in the art, e.g. laser,mechanical means or electrostatic means. The (e.g. laser perforated)perforations (hole) dimensions may be 0.1 mm to 0.7 mm along one or bothedges. The (e.g. laser perforated) perforations (holes) are preferablyspaced at 5 to 25 holes per cm (along the line of perforations), forexample 10 to 25 holes per cm (along the line of perforations), forexample 11 to 23 holes per cm (along the line of perforations).Preferably the perforations (holes) are of nominal dimensions 0.6 mm×0.3mm, e.g. 0.4×0.2 mm. Preferably perforations (e.g. oval holes) areoriented with their longest axis (i.e. the hole length) perpendicular tothe line of perforations.

The wrapper may be pre-perforated such that it has a line ofperforations extending from one end of the product rod to the other endand defining a helix about the periphery of the product rod. The wrappermay be a cellulosic film or a cellulosic based film. The wrapper may bebiodegradable. Preferably the wrapper has the ‘Ready Biodegradability’level of biodegradability as measured according to OECD 301B ‘ReadyBiodegradability’ method (modified Sturm test), which is well known inthe art.

Preferably the wrapper is a paper (e.g. plugwrap). The (e.g. individuale.g. pre-formed) filters and/or (e.g. individual e.g. pre-formed) filterelements in the flow (of filters or filter elements) are preferablyaligned such that the longitudinally axes of their cylindrical cores areoriented along the longitudinal direction of the flow.

The invention includes any filter cigarette made using a filteraccording to the invention.

The present invention will now be illustrated with reference to thefollowing Examples and the attached drawings in which FIG. 1schematically illustrates a product rod of filters according to anembodiment of the invention; FIG. 2 is a different view of the productrod of filters of FIG. 1; FIG. 3 schematically illustrates a method andapparatus which may be used to manufacture the product of e.g. FIGS. 1and 2; FIG. 4 illustrates a product rod of filters according to afurther embodiment of the invention; and FIG. 5 shows the results oftesting products of the invention (Example 1).

FIGS. 1 and 2 show a NWA “Rip-a-Tip”™ product rod 1 according to oneembodiment of the invention.

The product rod 1 comprises six individual tobacco smoke filters 3 eachof around 17.5 mm circumference and length 14 mm abutted end to end. Theindividual tobacco smoke filters 3 are identical with each other. Eachfilter 3 includes a self-sustaining substantially cylindrical coreformed from a plurality of longitudinally extending substantiallycontinuous filaments of crimped cellulose acetate tow which are bondedat their points of contact (i.e. each filter 3 is a NWA filter). Theproduct rod 1 also includes a wrapper 5 comprising paper of basis weight25 gsm which is engaged around the filters 3 thereby forming a wrappedcylinder of six filter elements of length 84 mm. As is best seen in FIG.2, the wrapper includes five lines of perforations 7, each lineincluding thirty oval holes of hole size about 0.6×0.3 mm (aligned suchthat the length of each oval hole is aligned with the longitudinal axisof the product rod 1). Each line of perforations 7 is in register with ajunction between two abutted filters 3 (in other words, in register witheach region where adjacent filters or filter elements abut each other).The holes in the wrapper can be made by any means known in the art, e.g.laser, mechanical or electrostatic means; suitable methods are describedbelow.

In use the smoker takes product rod 1 and pulls or bends the rod at thejoin closest to one end of the product rod (indicated by the line ofperforations closest to the end) to snap off an individual filter; thefilter is then used when rolling a RYO cigarette. The oval holes of holesize about 0.6×0.3 mm are sufficiently large that the consumer can seethem on the outside of the finished rod 3, enabling him to clearlyidentify the point at which the rod should be snapped. The lines 7 ofperforations (holes) enable a clean break between adjoining tips to beachieved—a jagged break would be unsightly and unacceptable to theconsumer. The section of the outer wrapper 5 around the individualfilter is retained and forms part of the filter to be used, rather thanbecoming redundant (and discarded) in the case of conventionalPop-a-Tips.

FIG. 3 shows a method and apparatus according to a further embodiment ofthe invention which may be used to manufacture the product of FIGS. 1and 2.

As can be seen in FIG. 3 a flow of pre-formed filters 103 and pre-formeddual filter rods 103 a is longitudinally advanced in the direction ofarrow 104 into a garniture unit 106.

The pre-formed (identical) filters 103 are each of around 17.5 mmcircumference and length 14 mm. Each filter 103 includes aself-sustaining substantially cylindrical core formed from a pluralityof longitudinally extending substantially continuous filaments ofcrimped cellulose acetate tow which are bonded at their points ofcontact. The pre-formed dual filter rods 103 a are each of around 17.5mm circumference and length 28 mm. Each rod 103 a includes aself-sustaining substantially cylindrical core formed from a pluralityof longitudinally extending substantially continuous filaments ofcrimped cellulose acetate tow which are bonded at their points ofcontact. The filters 103 are NWA filters and may, as well as dual rods103 a, be manufactured by a process similar to that described in UKPatent No. 1169932 (U.S. Pat. No. 3,455,766), in which filaments ofcellulose acetate tow to which a plasticiser has been applied are fedinto a forming station where a belt is folded around the tow until thelongitudinal edges of the belt are juxtaposed and the tow is confinedwithin the belt; the tow is thus formed into a longitudinally extendingcylinder by the belt. The belt is then moved to a heat treating stationwhere a heating fluid (e.g. steam) is passed through the belt intocontact with the tow to activate the plasticizer. The belt and towtherewithin are then moved through a cooling station where cool air orother fluid is passed through the belt into contact with the tow todeactivate the plasticizer, if necessary, and dry the tow by removal ofcondensed steam, whereby the tow is made rigid to form a continuous selfsustaining and stable longitudinally extending rod. The continuous selfsustaining and stable longitudinally extending rod is cut into base rodsof filters for subsequent use also by methods well known in the art.

Conventional Pop-a-Tip manufacture takes place on a dual rod filtermaking machine. These machines are well known in the art and normallyused for combining two different types of base rod, which are held intwo different hoppers on the machine. For Pop-a-Tip manufacture the twohoppers are filled with the same base rod type and these base rods arecut down (to provide the required tip length), aligned in an end-to-endrelationship, wrapped in transparent film and cut to the final requiredPop-a-Tip length. In the process of making product rods according to thepresent invention the two hoppers of the dual rod filter making machine(not shown) are also filled with base rods of filters 103 manufacturedas set out above. One hopper is used to cut down the base rods toindividual filters 103 of the required tip length (14 mm) and the otherhopper is used to cut down the base rods to dual filter rods 103 a ofthe required tip length (28 mm) and the dual rod machine is then set toarrange and align the filters 103 and dual filter rods 103 a in anend-to-end relationship such that each dual filter rod 103 is separatedform the next rod 103 a by four individual filters 103 to provide theflow of pre-formed filters 103 and multiple (dual) filter rods 103 a. Ascan be seen in FIG. 3 the filters 103 are aligned and abutted end to end(i.e. there are no spaces between individual filters 103 or filters 103and filter rods 103 a) prior to longitudinal advancement in thedirection of arrow 104 into the garniture unit 106.

The garniture unit 106 includes a compression shoe 108 through which thealigned and abutted filters 103 and dual filter rods 103 a are passedprior to wrapping in the garniture. Compression shoes are known in theart for control of the final circumference of the finished rod.

A wrapper 105 of paper of basis weight 25 gsm is applied to thecontinuously advancing flow of filters or filter elements in thegarniture 106 in the conventional manner, to thereby form a continuouswrapped rod 111 comprising groups of four individual filters 103separated by dual filter rods 103 a. The continuous wrapped rod 111 isthen cut in register with a position half way along each dual filter rod103 a (see arrow 222) by methods known in the art to provideintermediate product rods of around 17.5 mm circumference and 84 mmlength, each containing six individual, identical, 14 mm long filters103 in a common paper wrapper.

It is essential that each line of perforation holes (in the above casethese would be spaced 14 mm apart) are closely aligned with (in registerwith) the region where adjoining tips abut. This may be achieved by theuse of an on-line laser perforation system (not shown) after each filterrod (e.g. of 84 mm length) has been assembled. Such a laser perforatorgenerates holes around the periphery of the rod in defined locations ina manner that is well-known for the online perforation of filterventilation holes during cigarette assembly. The laser perforatorgenerates five lines of perforations around the periphery of the rod:each line includes thirty oval holes of hole size about 0.6×0.3 mm, e.g.0.4×0.2 mm; and each line of perforations is in register with a junctionbetween two abutted filters. The resulting perforated product rod is aproduct as shown in FIGS. 1 and 2.

It will be appreciated that there are other ways in which theperforations may be achieved, including: a) use of a pre-perforatedwrapper in which the perforations are aligned in rows across the widthof the wrapper, each row being separated from the adjacent row by adistance (e.g. 14 mm) corresponding to the length of the filter and thenemploying a suitable registration system to ensure that these rows aremaintained in alignment with the flow of filter tips during filter rodassembly; and b) a system similar to (a) in which, rather than thewrapper being pre-perforated, a series of lateral perforation lines aregenerated in the (non-perforated) wrapper as part of the filterproduction process immediately prior to it being used to wrap the filtertips.

FIG. 4 shows a NWA “Rip-a-Tip”™ product rod 51 according to anotherembodiment of the invention.

The product rod 51 comprises six individual (identical) tobacco smokefilters 53 each of around 17.5 mm circumference and length 14 mm abuttedend to end. Each filter 53 includes a self-sustaining substantiallycylindrical core formed from a plurality of longitudinally extendingsubstantially continuous filaments of crimped cellulose acetate towwhich are bonded at their points of contact (i.e. each filter 53 is aNWA filter). The product 51 also includes a wrapper 55 comprising paperof basis weight 25 gsm which is engaged around the filters 53 therebyforming a wrapped cylinder of six filter elements of length 84 mm. Thewrapper includes a lines of perforations 57 extending from one end ofthe product rod 51 to the other (end) and defining a helix (spiral)about the periphery of the product rod. The perforations are oval holesof hole size about 0.4×0.2 mm.

The holes in the wrapper can be made by any means known in the art, e.g.laser, mechanical or electrostatic means, e.g. by the methods describedabove. It will be appreciated that if the wrapper is pre-perforated(i.e. perforated before application to the filters/elements of theproduct rod), the perforations (holes) will have to be carefully locatedso they form a continuous helix after the wrapper is wrapped around thefilters/elements.

In use of the embodiment of FIG. 4, the consumer peels back a strip ofthe wrapper along the helical line of perforations to allow individualfilter tips to be sequentially released for use; the remaining portionof the wrapper holds the remaining filters in place. It will beappreciated that in this case the wrapper is discarded, rather thanremaining part of the filter.

In another example (not shown) the pitch of the helix defined by theline of the perforations 57 (that is the distance along the helical axisand also along the product rod that results in one full turn of thehelix) may be 14 mm, the length of a single individual filter or filterelement. In this example, peeling back a single turn of the helix of thewrapper releases a single filter/filter element.

EXAMPLES Example 1

The applicants carried out trials to identify the most appropriate sizeand spacing of holes to enable (i) a clean break, or “snap” of thefilter from the product rod and (ii) a suitable visual cue for theconsumer.

The applicants made filter rods (of 17.9 mm circumference) similar tothose shown in FIGS. 1 and 2, using NWA filters and a perforatedplugwrap paper. The plugwrap paper was perforated with various numbersof either rectangular or oval holes of nominal dimensions 0.2×0.4 mm(with the length of hole orientated along the length of the paper/filterrods—in other words the holes are oriented with their longest axis (i.e.the hole length) perpendicular to the line of perforations).Measurements subsequently made using a microscope showed that the actualhole size was closer to 0.6×0.3 mm.

The manufactured rods were tested by “snapping” or pulling off onefilter from the rest along the line of the perforations.

The following Table shows the results.

Number of holes Rectangular holes Oval holes 10 Uneven “snap”/tearingUneven “snap”/tearing 15 Uneven “snap”/tearing Uneven “snap”/tearing 20Uneven “snap”/tearing Fair ease of separation and quality of separationline 25 Fair ease of separation Good ease of separation and quality ofseparation and quality of separation line line 30 Good ease ofseparation Very good ease of and quality of separation separation andquality line (see FIG. 5) of separation line (see FIG. 5) 35 Very goodease of Excellent ease of separa- separation and quality tion andquality of of separation line; separation line; rod rod unstable/weakunstable/weak

In all cases, the oval hole shape provides a smoother and more evenseparation line after ripping (“snapping”) an individual filter off therod (FIG. 5).

The best results in terms of ease of separation and the quality of theseparation line were obtained with 35 holes for rectangular hole shape;however, similar results were obtained with 30 holes for the oval holeshape (FIG. 5), and even better results in terms of ease of separationwere obtained with 35 holes for oval hole shape. However, with 35 holesthe rod became unstable and there is a risk of significant difficultyprocessing the plugwrap with this pattern in production and of the rodbecoming unstable during packaging and transportation. Thus, the patternwith 30 oval shaped holes provides the best results in terms of ease ofseparation, rod stability and the quality of the separation line.

The example therefore shows that 30 to 35 rectangular or oval shapedholes of nominal dimensions 0.4×0.2 mm around the circumference of a17.9 mm circumference Pop-a-Tip provide optimum ‘snap’ characteristics(see FIG. 5). Less than around 15 holes of such size give an uneven‘snap’, whilst more than 35 or 40 holes can result in the paper beingtoo weak to be processed on conventional filter making or packagingmachinery.

Example 2

This Example measures the tensile strength of a plug wrap that has beenperforated in accordance with aspects of the invention. The test isdesigned to assess the runnability of a pre-perforated paper on a filtermaking machine.

Strips of non-porous plug wrap paper of 27 gsm basis weight as suppliedby Papierfabrik Wattens GmbH of Austria were perforated by laserproviding an array of holes each nominally 0.4×0.2 mm. An array of holeswere produced at 10, 20, 30, 40, 50 and 60 holes per 17.5 mm width andthe tensile strength measured.

The results were as follows:

Number of Holes/17.5 mm Mean Tensile Strength (Kgf) 0 2.29 10 2.35 202.23 30 1.78 40 1.75 50 1.47 60 1.39

The test method involved cutting the plug into test pieces of 180 mmlength×15 mm width, with each test strip having a single line of holes.Testing was carried out using a Lloyd L500 tensile tester, using a loadrange of 0-10.0 Kgf , extension range 0-1000 mm and crosshead speed setto ensure that the sample broke within 15 to 25 seconds.

A surprisingly high level of tensile strength was retained, even at themore extreme number of holes where the paper was visually almostcompletely cut through.

These data confirm the runnability of the plug wrap on filter makingmachines: even at the highest preferred level of 40 holes per 17.5 mmwidth, the loss of tensile strength was only around 25%.

1. A method of forming a cigarette: providing a plurality of individualtobacco smoke filters or filter elements abutted end to end; engaging awrapper around the plurality of filters or filter elements; perforatingthe wrapper with a line of 16 to 39 perforations in register with eachjunction between abutted filters or filter elements; removing at leastone of the tobacco smoke filters or filter elements from the rest of thetobacco smoke filters or filter elements; and employing the at least oneof the tobacco smoke filters or filter elements removed from the rest ofthe tobacco smoke filters or filter elements as a filter while rollingthe cigarette.
 2. The method according to claim 1 wherein the individualtobacco smoke filters, or individual tobacco smoke filter elements, areidentical or substantially identical.
 3. The method according to claim 1wherein the wrapper is paper or other sheet material.
 4. The methodaccording to claim 3 wherein the paper has basis weight of 15-50 gsm. 5.The method according to claim 1 wherein the perforations aresymmetrical.
 6. The method according to claim 1 wherein the perforationsare oval or rectangular.
 7. The method according to claim 1 wherein theperforations are of approximate dimensions 0.1 mm to 0.7 mm.
 8. Themethod according to claim 1 wherein the perforations are spaced at 10 to25 holes per cm.
 9. The method according to claim 1 wherein: removing atleast one of the tobacco smoke filters or filter elements from the restof the tobacco smoke filters or filter elements includes removing aportion of the paper around the removed at least one of the tobaccosmoke filters or filter elements; and further including maintaining theportion of the paper around the removed at least one of the tobaccosmoke filters or filter elements while rolling the cigarette.
 10. Themethod according to claim 1 wherein the individual tobacco smoke filtersor filter elements include a substantially cylindrical core of tobaccosmoke filtering material.
 11. The method according to claim 1 whereinthe individual tobacco smoke filters or filter elements include aself-sustaining longitudinally extending cylindrical core of tobaccosmoke filtering material.
 12. The method according to claim 1 whereinthe individual tobacco smoke filters or filter elements include aself-sustaining longitudinally extending cylindrical core comprising aplurality of longitudinally extending substantially continuous filamentsof tobacco smoke filtering material which are bonded at their points ofcontact.
 13. The method according to claim 1 wherein the individualtobacco smoke filters or filter elements include a self-sustaininglongitudinally extending cylindrical core comprising a plurality ofrandomly oriented fibres of tobacco smoke filtering material which arebonded at their points of contact.
 14. The method according to claim 1wherein the individual tobacco smoke filters or filter elements includeone or more continuous components extending substantially longitudinallyof the cylindrical core.
 15. A method of forming a cigarette: providinga plurality of individual tobacco smoke filters or filter elementsabutted end to end; engaging a wrapper around the plurality of filtersor filter elements; perforating the wrapper with a line of perforationsextending from one end of the product rod to the other end and defininga helix about the periphery of the product rod; removing at least one ofthe tobacco smoke filters or filter elements from the rest of thetobacco smoke filters or filter elements; and employing the at least oneof the tobacco smoke filters or filter elements removed from the rest ofthe tobacco smoke filters or filter elements as a filter while rollingthe cigarette.
 16. The method according to claim 15 wherein the pitch ofthe helix defined by the line of the perforations is the length of asingle individual filter or filter element.
 17. The method according toclaim 15 wherein the perforations are symmetrical.
 18. The methodaccording to claim 15 wherein the perforations are oval or rectangular.19. The method according to claim 15 wherein the perforations are ofapproximate dimensions 0.1 mm to 0.7 mm.
 20. The method according toclaim 15 wherein the perforations are spaced at 5 to 25 holes per cm.21. The method according to claim 15 wherein the individual tobaccosmoke filters, or individual tobacco smoke filter elements, areidentical or substantially identical.
 22. A method of forming acigarette: providing a plurality of individual tobacco smoke filters orfilter elements abutted end to end; engaging a wrapper around theplurality of filters or filter elements; perforating the wrapper with aline of 16 to 39 perforations in register with each junction betweenabutted filters or filter elements; removing one of the tobacco smokefilters or filter elements from the rest of the tobacco smoke filters orfilter elements; and employing the one of the tobacco smoke filters orfilter elements removed from the rest of the tobacco smoke filters orfilter elements as a filter while rolling the cigarette.